The present invention relates generally to powerboat motors and more particularly to alarms and ignition disabling systems for powerboats that are responsive to the absolute tilt position of an outboard motor.
Systems that provide position sensing and response capability when a predetermined position of an object occurs have been disclosed for a variety of applications such as vehicle theft prevention, medical patient monitoring, earthquake detection, and to a limited extent, marine motors. Position sensing is generally accomplished in the related art with mercury switches, transducers and comparator circuits, variable resistance devices, infrared detectors, and other electrical devices. When a threshold position or condition has been registered by the position sensor, the sensor transmits a signal to a response device such as an alarm to warn an operator of an undesirable position of the object.
Devices and methods for position sensing, or tilt indication, of outboard motors are numerous and well known in the art. The devices generally provide an indication as to the absolute position or trim of the outboard motor through a visible analog gauge, hereinafter referred to as a trim position indicator, mounted on the instrument panel of the helm. A variety of electrical sensors are provided in the related art to detect the trim position and to subsequently communicate the absolute position of the outboard motor to the trim position indicator.
One such trim position sensor is disclosed in U.S. Pat. No. 4,459,115 to Ballard, wherein an electrically conductive ball is employed that rides on individual electrical contacts to sense the position of the outboard motor. The position sensor of Ballard senses the position of the propeller with reference to the water line rather than relative to the transom. Additional trim position sensors are disclosed in U.S. Pat. No. 4,005,674 to Davis, wherein the position of electrical contacts are varied with successive pivoting of the outboard motor, and also in U.S. Pat. No. 3,641,965 to Schmiedel that employs a variable resistor with linear variable resistor cards to sense and indicate trim position. The related art trim position sensors, however, are limited to sensing the absolute position of the outboard motor and indicating such position on the trim position indicator.
The trim position sensors of the related art do not appear to communicate with the ignition system of a powerboat so as to produce an alarm or disabling signal if the outboard motor is in an undesirable tilt position. More specifically, the related art does not warn or prevent an operator from starting the outboard motor if the outboard unit is improperly trimmed out of the water. For example, if the outboard motor is trimmed too high out of the water such that the water pump intake on the outdrive unit is out of the water, the water pump is deprived of necessary lubrication and can subsequently overheat and eventually fail. Moreover, water pump failure can lead to overheating and failure of the entire outboard motor. Additionally, the exhaust that exits from the exhaust port of the outdrive unit becomes extremely loud, thereby disturbing the operator, the passengers, and fellow boaters.
Accordingly, there remains a need in the art for a system that can warn and/or prevent a powerboat operator from starting the outboard motor if the outboard motor is improperly tilted out of the water. The device should also be inexpensive and capable of being easily retrofitted into existing powerboat systems.
In one form, the present invention provides an outboard motor position responsive device to inhibit or prevent a powerboat operator from engaging the ignition system while the outboard motor remains improperly tilted out of the water, i.e. beyond a maximum safe tilt position. The position responsive device generally comprises an outboard motor position sensor that is in communication with an existing ignition system of a powerboat. The outboard motor position sensor sends a signal to an alarm and/or an ignition disabling switch when the outboard motor is tilted up beyond the maximum safe tilt position. Accordingly, the alarm warns the operator of the undesirable tilt position and the ignition disabling switch disengages the ignition system so that the outboard motor cannot be started. Further, either an alarm or ignition disabling may be employed, or both an alarm and ignition disabling may be employed by the outboard motor position responsive system of the present invention.
The outboard motor position sensor is preferably a voltage comparator circuit that is in communication with an existing trim position indicator of a powerboat. Existing trim gauges generally include a potentiometer mounted on the tilt axis of an outboard motor, thereby presenting a graphical reference of tilt position rather than specific voltage readings from the circuit. Similarly, the voltage comparator circuit of the present invention further comprises a potentiometer that is used to adjust a reference voltage that corresponds to the maximum safe tilt position of the outboard motor. When the reference voltage is approached, the voltage comparator circuit activates the alarm and/or the ignition disabling switch to warn the operator of the undesirable tilt position of the outboard motor.
In another form, the position responsive device further comprises an interval-on relay in communication with the outboard motor position sensor to activate the alarm or the ignition disabling switch for only a predetermined amount of time. Accordingly, the operator experiences the alarm and/or the ignition disabling switch as a warning only for a predetermined amount of time prior to starting the outboard engine. The operator may then engage the outboard motor and proceed at their own risk. The interval-on relay also prevents against wave-induced alarms or activation of the ignition disabling switch due to slight changes in voltage from the oscillatory or xe2x80x9cbouncingxe2x80x9d action of the powerboat traversing through the water.
In other forms, the outboard motor position sensor may comprise other devices that sense the tilt position of the outboard motor. Such devices may include, for example, a mechanical limit switch, a proximity switch, a mercury switch, an optical switch, or a water sensing device, among others, as described in greater detail below.
In one form, the alarm is an audible electric buzzer that is easily heard by the powerboat operator. In other forms, the alarm may comprise, for example, a light such as an LED (light emitting diode) mounted to the helm, or a computerized voice warning, among others. In addition to disabling the ignition system, responsive devices that initiate automatic lowering of the outboard motor to a proper tilt position prior to engaging the ignition system are also provided.
Communication amongst the outboard motor position sensor, the interval-on relay, the alarm, the ignition disabling switch, and other system components may be accomplished by conventional hard wiring, infrared (IR) signal transmission and reception, or radio frequency (RF) signal transmission and reception, among others. Further, signals may be superimposed over existing powerboat hard wiring to minimize the need for additional hard wire connections.
The present invention also provides a junction box that houses the components of the position responsive system, which is easily retrofittable with existing ignition systems of powerboats. The junction box is relatively small and further comprises adjustment screws that correspond with potentiometers that adjust the amount of time that the alarm and/or the ignition disabling switch remain activated and that adjust the reference voltage that corresponds with the maximum safe tilt position of the outboard motor.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.